Process and apparatus for converting hydrocarbons



w M CROSS 1,825,338

PROCESS AND APPARATUS FOR CONVERTING HYDROCARBONS GRO.

OOO OOO OOO Ima! Filed Feb. l, 1926 Petented sept. 29,1931

UNITED srArEs PATENT OFFICE' WALTER I. CROSS, OF KANSAS CITY, MISSOURI, ASSIGNOR, .'BY' MESNE ASSIGNMENTS,

TO GASOLINE PRODUCTS COMPANY, INC.,

TION OF DELAWARE OF WILMINGTON, DELAWARE, A CORPORA- PROCES AND APPARATUS FOR CONVERTING HYDROCARBONS Application mea February 1, 192e. serial no. 35,157. l

and utilizing the air preheated during this dephlegmation of the hydrocarbonk fractions for the entering air to the furnace. Furthermore, noveltydies in the particular type of heat exchanger which is used as the element of heat exchange between the air stream and the vapors rising through the dephlegmating stage or column.

ig. 1 is a diagrammaticside elevational view of an apparatus in which the method and device may be economically utilized, but it should be understood that the scope of the zo invention is not to be limited to the particu-- lar embodiment shown as it can be asl well applied to any type of apparatus in which it is desirable to separate or knock back the higher boiling point fractions and at the same 85 time procure a preheated entering air for the heater or furnace.

Fig. 2 is a sectional detail of the heat exchanger.

In the drawings is shown the invention in ,onnection with the cross cracking process,- the details of which have been simplified as the operation is Well known in the art and forms no part of the present invention other than to disclose an apparatus upon which the invention may be used.

Referring to the drawings, at 1 is shown afurnace consisting of a fire chamber 2 and a tube chamber 3 in the latter being mounted the heating tubes 4; 5 is a chimney or stack; 6 is a reaction chamber connected to the discharge from the heating tubes by the transfer line 7. The reaction chamber is preferably fabricated from asingle ingot by forging, having fianged bottle-neck ends closed by means of removable plates which facilitate the cleaning thereof. It is also heavily insu-v lated to prevent loss of heat by radiation. The evaporator 8 is connected to the discharge from the reaction chamber throughv a transfer line 9 in which is interposed a pressure reduction valve 10. At 11 is shown a dephlegmator or reiluxing tower preferably of the bubble type connected with\the evaporator 8 by means of a vapor line 12. An overhead vapor line from the tower 11, designated as 13, communicates with the condenser coil 14 positioned in the condenser box 15. The discharge end of the condenser coil 14 terminates in a pipe 16 which communicates with the gas separator 17, the latter being equipped with a liquid draw olf line 18 controlled by a valve 19 and a gas draw olf line 20 controlled by a valve` 21.

In operation, charging stock, supplied to the stock tank 22 from any convenient source through the line 23, is directed through the line 24 and charged, by means of pumps 25 and 26, to the coils 4 where it is raised to a cracking or conversion temperature. The velocity of the oil through the coils and the heating being so regulated that a minimum amount of carbon or polymerized products are separated. out due to the heating. The oil is suiiiciently heated in the coil so that upon its discharge through the line 7 it accumulates in the reaction chamber 6 to substantially consummate the conversion which was initiated in the coil. This conversion is due primarily to the time period that the oil is maintained in the reaction chamber and tvhe it undergoes. In practice, the temperatures and pressures are regulated to prevent substantial vaporizatio On discharge from the reaction chamber, the high pressure is released and the lighter fractions are permitted to evaporate from the oil body in the evaporating tower 8. Steam ora cooler hydrocarbon may be introduced through the pipe 27 controlled by a valve 28 90 to regulate the degree of evaporation and the characterof bottom' which-is drawn off from the tower through the line 29 controlled by a valve 3Q, theA latter valve being manipulated either manually or mechanically by a liquid level regulating device not shown. The products withdrawn from the evaporator are directed to a cooler 31 and thence to storage through the pipe 32. The overhead matetroduced into the bottom of the reluxing tower and rises in an opposed direction to a gravitating liquid condensate which is constantly being separated from the vapors in the column. This condensate collecting in the bottom of the tower is drawn oli' through the pipe 33 and may be directed immediately to the charging pipe 24 or diverted through the line 34 to the tank 22 by manipulation of the valves 35 and 36.

The control of the outlet temperature of the vaporous fractions from the tower 11 by means of a relatively cooler air stream is accomplished by means of a heat exchanger 37 which is positioned at or in the top of the tower 11. This heat exchanger preferably comprises a plurality of sets of corrugated sheets arranged in the manner described in my previous applications Serial No. 35,571, dated June 8, 1925, and Serial No. 79,772, dated January 7, 1926.I T wo corrugated sheets are combined to form a set designated as 38 in Fig. 2. These sets are arranged in the manner shown in Fig. 2 and the vapors permitted to rise vertically through the sinuous or tortuous ducts 39. The air, on the other hand, is introduced from the atmosphere through the duct 40 and circulated by means of a blower fan 41 driven by a motor 42 and directed to the header 43 communicating with the straight tube-like ducts 44. lin the drawings, the stream of air is shown as passing but once through the tower but it y should be understood that the stream may be reversed as many times as it is found necessary to procure the desired amount of cooling and greatest eilciency of heat exchange. This may be accomplished by providing conduit 51 provided with valve 52 bv means of which air, after passing through the heat ex changer. may be returned to the low pressure side of the blower. The air utilized in this manner as a refluxing medium is preheated kand is discharged from the exchanger through the duct 44a and introduced to the ire chamber 2 of the furnace 1. This preheated air considerably increases the eiliciencv of the furnace as it 'reouires considerably less heat to bring up the temperature of the combustion gases to the desired degree if the air introduced to the fire chamber is at a relatively high temperature. This practice of utilizing an air stream as a reluxing medium and employing the preheated air as the entering air to the furnace. may be supplemented. if desired. by recycling a portion of the hot stack or Hue gases if these gases are above the temperature of the preheated air; if, however. they are below this temperature, theirrecycling would' not improve the eiiiciency as thev would tend to lower the temperature of theair entering the furnace.

AIt is of importance in the conversion of hydrocarbon oils to control within a relatively limitedn range the character of the'mateis positioned in the top of the tower which has electrical connections 46 with a relay switch 47, the latter regulating the speed of 'the motor 42 which drives the fan 41, resulting in the varying in the volume of air which is introduced and circulated through the heat exchanger.

A discharge pipe 48 and dampers 49 and 50 serve to control the amount of air which is introduced to the furnace and maintain a relatively constant supply. Such control in a heating stage, passing the heated oil to conversion, evaporating and dephlegmating'l stages and controlling the character of the vapors discharged from the dephlegmating stage by submitting the vapors to heat exchange relationship with a mechanically driven cool airA draft regulated to eect said control; passing air preheated by the discharged vapors to the heating stage, and returning a portion of the preheated air to the lmay be necessitated by a variance or change 585 cooler air draft, whereby the said air draft.,

is maintained at a predetermined temperature.

2. 1n an apparatus of the character described comprising heating and dephlegmating devices, in combination, mechanically..

driven cool air draft means and an associated heat exchanger positioned on the dephlegmator, an air duct leading from the heat exchanger to the heater and adapted to deliver heated air thereto, `and means for recycling the heated air.

3. An apparatus for treating oil comprising a furnace, a heating element in the furnace through ywhich oil to be treated is passed, a vaporizer adapted to receive thel heated oil, a dephlegmating tower, means for conveying vapors from the vaporizer to the dephlegmating tower, said tower having a vapor discharge outlet. a heat exchanger associated with said outlet for cooling vaporsl passing from the-tower, means for `forcing air through sa1d heat exchanger in heatexchange relation with the vapors, a conduit connecting the air discharge portion of said heat exchanger with the furnace for supplying preheated air to the latter, andmeans ill! Y 'aan connecting said conduit with the low pressure side of the air forcing means for recycling a portion of the air discharged from the heat Y exchanger.

5 4. In an oil treating apparatus, a de. phlcgmating tower, means in said tower for dephlegmatmg vapors passing therethrough, means for introducing vapors into the tower, said tower having a vapor discharge outlet,

w a heat exchanger associated therewith for cooling vapors passing from the tower, a blower associated with the heat exchanger for forcing a current of air therethrough in heat exchange relation with vsaid vapors, said 15 heat exchanger having a discharge outlet for air passing therethrough, and a conduit associated with the air discharge outlet and connected with a low pressure portion of said blower for recirculating a portion of the dis- 20 charged air through the heat exchan er.

WALTER M. CR SS. 

